T&T: Onan Generator Fuel Stop Solenoid

[Alan Shapiro via Trawlers-and-Trawlering]

I have the Onan MDJE 7.5 diesel generator on my Gulfstar 43. Although it
turns over very well, it won't catch. I, and my boatyard buddies, think
the problem is the fuel stop solenoid - it won't stay up and if I prop
it up the motor will still not catch. The parts manual lists 2
solenoids, based on before and after a particular serial number of the
generator. Mine is the earlier and the part number for the solenoid kit
is 307-2026. The later, more traditional looking solenoid is part number
307-1904.

For my solenoid, 307-2026, the cost is outrageous and availability is
next to, but not quite, zero: about $750. But the later model solenoid
with its traditional solenoid look, can be had for slightly more than $100!

My question is: can I simply use the less expensive 307-1904?

If so, I will also have a particular wiring question, but for now can
anyone help save me a bundle of money?


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[Rudy Sechez via Trawlers-and-Trawlering]

Any chance that you can take it to NAPA and see if they can match your solenoid?

Rudy and Jill Sechez
Ft Pierce, FL
BRINEY BUG-a 34' Sail-Assisted Trawler
850-832-7748
anchoringconsultants.com, & the book...
"ANCHORING-A Ground Tackler's Apprentice"

[Rich Gano via Trawlers-and-Trawlering]

I had the same Onan in the Calypso (GB42), and I got rid of the original
solenoid which looked like a short cylinder in favor of the UPDATE kit which
came with a new steel mounting plate and a more slender looking and taller
solenoid (307P773 is the part number I have recorded). I also removed the
original solenoid switches from the control box and replaced them with a
modern looking clear plastic box type with an included plastic plug-in base
- all part of another UPDATE kit from Onan/Cummins. After a few years, the
new solenoid failed, and I read the manufacturer's name off the coil and
managed to get a new one for 80 bucks and just replaced the failed coil
without a lot of fuss. I also purchased a spare solenoid for the updated
control box solenoid mostly for use in eliminating the one in service as a
problem when troubleshooting.

Other starting issues could be the centrifugal switch, a break in the wire
running to the fuel solenoid from the heat sensor on the side of the engine,
battery not fully charged, interrupted ground for the fuel solenoid, and bad
glow plugs.

Rich Gano
FROLIC 2005 Mainship 30 Pilot II
Panama City, FL

> I have the Onan MDJE 7.5 diesel generator on my Gulfstar 43. Although it
> turns over very well, it won't catch. I, and my boatyard buddies, think
the
> problem is the fuel stop solenoid - it won't stay up and if I prop it up
the
> motor will still not catch. The parts manual lists 2 solenoids, based on
before
> and after a particular serial number of the generator. Mine is the earlier
and
> the part number for the solenoid kit is 307-2026. The later, more
traditional
> looking solenoid is part number 307-1904.
>
> For my solenoid, 307-2026, the cost is outrageous and availability is next
to,
> but not quite, zero: about $750. But the later model solenoid with its
> traditional solenoid look, can be had for slightly more than $100!
>
> My question is: can I simply use the less expensive 307-1904?

[Jorge via Trawlers-and-Trawlering]

We had the same on our Gulfstar. If you take the end cap off of the solenoid you will find a set of points like the old car distributor. Run an emery board between the contacts and try it. It fixed our issue. You can also go to an alternator or starter shop and they will rewind it.

Sent from my iPhone

[Alan Shapiro via Trawlers-and-Trawlering]

Thanks to all for their suggestions, although I would still like to know
if the later solenoid would do the job.

In the meantime I can say with certainty that the problem is not the
battery nor is it the glow plug (which is not in the block but rather is
in the air intake and can be seen to be working properly).

If I don't hear anything about the later solenoid I may just take a
chance on it and order one on the net.

And the idea of removing the existing solenoid and having it checked out
by an alternator rewinding shop is certainly worth trying. Jorge, did
you have any difficulty opening the solenoid?

Thanks again to all.

[Frank Burrows via Trawlers-and-Trawlering]

Alan:

A couple of thoughts. The solenoid on the front of your generator pulls
back a lever to enable the generator to start and run. If you watch the
solenoid, it should pull in when you are cranking the engine with the
starter. If it does not do anything then check to see if it is getting
12 volts. If you manually pull the solenoid in and try to start the
generator it should start and run until you release the solenoid.

The solenoid has two coils. The pull coil is stronger and pulls more
amps and pulls in the solenoid. The hold coil is weaker, pulls less amps
and holds the solenoid plunger. The switch is internal and those are the
contacts mentioned by Jorge. One source of failure is that the pull
portion stays engaged and overheats the solenoid. The pull portion is
meant to be only momentarily engaged until the hold portion takes over.
The hold portion is engaged as long as the generator is running.

You can get more info on this at BoatDiesel.com. You have to pay $25
annually but they have a huge amount of info in their forums on diesel
engines and generators and it is well worth the money.

FWIW if the solenoid is bad I would certainly use the cheaper one.

Good luck

Frank Burrows    79 43' Viking   Piney Narrows  Chesapeake Bay

On 3/14/2018 7:35 PM, Alan Shapiro via Trawlers-and-Trawlering wrote:
> Thanks to all for their suggestions, although I would still like to
> know if the later solenoid would do the job.
>
> In the meantime I can say with certainty that the problem is not the
> battery nor is it the glow plug (which is not in the block but rather
> is in the air intake and can be seen to be working properly).

[Alan Shapiro via Trawlers-and-Trawlering]

This list is nothing short of amazing.

The members who suggested that what I observed glowing was not a glow
plug but an air warmer are clearly correct. Next time in Florida t the
boat, I'll find the glow plugs and check them. I'll also try taking off
the existing fuel stop solenoid and try to clean up the contacts and/or
take it in for a rewinding. But simply holding up the "piston" doesnt
seem to work. At the same time, I'm going to try installing the later
model solenoid. For $100 it's worth a shot.

Thanks again to all.

[Rudy Sechez via Trawlers-and-Trawlering]

If it is the shut-down solenoid, then replacing it would be
appropriate. However, if the glo plugs are not heating up, that too
could prevent the engine from starting. On my Westerbeke, it has
wiring that comes off two smaller posts on the solenoid, which then go
to the glo plugs. These smaller posts can stop passing current, even
though the large posts on the solenoid still work. On our engine, the
symptoms of this was that the glo plugs would not heat up and the
engine required considerable cranking to start. A failure to pass 12v
through the solenoid, from small post to small post, when the
solenoid was activated diagnosed the problem.

Rudy and Jill Sechez
northbound, north of Vero Bch, Fl

BRINEY BUG-a 34' Sail-Assisted Trawler
850-832-7748
anchoringconsultants.com, & the book...
"ANCHORING-A Ground Tackler's Apprentice"

[patrick Benvenutti via Trawlers-and-Trawlering]

Also check all of your safeties, ( oil pressure, Eng. Temp, etc. )ohm and or jump them out to see if they are keeping the Solenoid From energizing.

Sent from my iPhone

> On Mar 15, 2018, at 1:43 PM, Rudy Sechez via Trawlers-and-Trawlering <traw...@lists.trawlering.com> wrote:
>
> If it is the shut-down solenoid, then replacing it would be
> appropriate. However, if the glo plugs are not heating up, that too

> could prevent the engine from starting. On my prohibited.

[Ken Buck via Trawlers-and-Trawlering]

That's a new one for me. I was under the impression that you had either an intake air heater OR glow plugs, not both. Please let us know if you find plugs too. 
 
Ken
 
In a message dated 3/16/2018 9:00:33 AM US Mountain Standard Time, trawlers...@lists.trawlering.com writes:

 
Onan Generator Fuel Stop Solenoid